With the increasing social needs for safety and feeling of safety during vehicle driving, what has become common practice in recent years is capturing images of the area behind a vehicle with a vehicle-mounted camera and displaying the images on a screen such as a monitor to show the images to a driver. This enables the driver to check, in the images, the state of the area behind the vehicle, which is likely to be a blind area, and determine the presence or absence of obstacles such as pedestrians. This reduces the number of accidents occurring when vehicles moves backward.
In that case, however, when the driver misses obstacles in the captured images or fails to check the captured images, the driver may move the vehicle backward without noticing obstacles appearing in the captured images.
To overcome the above problem, for example, PTLs 1 and 2 discloses apparatuses that issue an alert to instruct a driver to sec the screen displaying captured images upon detecting obstacles appearing in the captured images. The apparatuses disclosed in PTLs 1 and 2 (hereinafter referred to as “conventional apparatuses”) detect an obstacle by, for example, image recognition or position detection when the obstacle appears in the captured images. Upon detecting the obstacle in the captured images, the conventional apparatuses issue an alert to the driver by sounding an alarm or automatically stopping the vehicle until the driver makes some designated operation through the screen displaying the captured images. With this configuration, the conventional apparatuses can surely prompt the driver to check the captured images upon detecting the obstacle in the captured images.